什么时候包括处理静态功能？

Consider the following:

class MyClass { 
    public static function MyIncludingMethod() {
        include_once("includes.php");
    }

    public static function MyOtherMethod() {
    }
}

Assuming this is valid- when will includes.php be included?

Option 1) When the php file containing all of this is included

Option 2) When MyClass::MyIncludingMethod() is called

Option 3) When anything from MyClass is called, even if MyClass::MyIncludingMethod() has not been called

includes.php:

<?php
  touch('i_was_called.txt');
?>

Results

1. No
2. Yes
3. No

Everything is as expected :)